Although computers today are far more powerful and compact than their predecessors, they still contain a number of components that require power and emit a significant amount of heat when operational. Most computers rely on active cooling devices such as fans to control the heat within the computer that intensifies as the computer operates. Typically, the fans are an integral component of the computer. For example, most Pentium®-class computers have two fans. One fan is generally visible from the back of the computer and cools the power supply. The other fan is inside the computer and cools the processor.
Despite the pervasive reliance on cooling fans, they are often the first components of a computer to fail. While a fan is an inexpensive component, the damage that can result to an improperly cooled computer can be very expensive. When excessive heat collects inside the computer, it can damage the CPU, hard disk, motherboard, and other expensive parts of the computer. It is essential, therefore, to try to detect a computer fan failure before the heat causes other failures in the computer.
Fan failures contribute to higher computer maintenance costs in at least two ways. First, maintenance costs are incurred when the failed fans must be repaired or replaced by a technician. Costs are further increased when additional components or the entire computer must be repaired or replaced because the fan failure was not corrected in time to prevent overheating of the other computer components. Costs related to reliability and damage can be significant for businesses that use a large number of computers.
There are other disadvantages to using fans to cool computers. In addition to being costly, computer fans are noisy and they draw dust as they draw air into the computer. The dust can contribute to the fan failures that result in increased maintenance costs. Additional costs may be incurred as attempts are made to control the environment and reduce the level of dust. These disadvantages make actively cooled computers less desirable for applications where noise and dust as well as reliability are a concern such as in hospitals, libraries, schools, etc.
Some computer manufacturers have recognized the advantages of actively cooled computers and have developed passively cooled computers. For example, U.S. Pat. No. 6,324,056 describes a passive cooling device for flat desktop personal computers. U.S. Pat. No. 5,729,431 describes a heat sink also for use in a personal computer. Although passively cooled computers are known, they do not have integrated displays and therefore, are not suitable for many applications in which limited space is available.